[NTP Snippets] Schedule periodic fetching

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsController.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsController.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsController.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsController.java
index 55dd84cddfe5c06bf900d50b78db2903f04fc62e..847b88c33ee11cf8315860f6bbb3e70df11c4c22 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsController.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsController.java
@@ -7,6 +7,7 @@ package org.chromium.chrome.browser.ntp.snippets;
 import android.content.Context;
 
 import org.chromium.base.ThreadUtils;
+import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.signin.SigninManager;
 import org.chromium.chrome.browser.signin.SigninManager.SignInStateObserver;
@@ -20,7 +21,10 @@ public class SnippetsController implements SignInStateObserver {
     private long mNativeSnippetsController;
 
     public SnippetsController(Context applicationContext) {
-        SigninManager.get(applicationContext).addSignInStateObserver(this);
+        // applicationContext can be null in tests.

[Bernhard Bauer, 2016/02/18 10:32:40]

Nit: Use pipe symbols for variable names, otherwise it reads a bit strange.

[Marc Treib, 2016/02/18 10:52:40]

Done.

+        if (applicationContext != null) {
+            SigninManager.get(applicationContext).addSignInStateObserver(this);
+        }
     }
 
     /**
@@ -55,5 +59,10 @@ public class SnippetsController implements SignInStateObserver {
     @Override
     public void onSignedOut() {}
 
+    @VisibleForTesting
+    public static void setInstanceForTesting(SnippetsController instance) {
+        sInstance = instance;
+    }
+
     private native void nativeFetchSnippets(Profile profile, boolean overwrite);
 }